Dual diaphragm distributor

ABSTRACT

A vacuum motor having two independently mounted and movable flexible diaphragms mounted in a common housing and partitioning the housing into fluid chambers, one of the diaphragms having a limited movement and at times limiting the movement of the other diaphragm, the other being connected to a means to be actuated.

United States Patent Kittredge 1 July 25, 1972 [54] DUAL DIAPHRAGMDISTRIBUTOR 3,385,275 5/1968 Burnia et all. ..123/117 3,362,297 1/1968Cripe ..92/48 X [721 Invenm Frank Kimedge, Temperance, Mlch- 3,352,20911/1967 Cripe 92/49 x 73 A F d M t C a D b h. 2,837,1l9 Schwartz 6181 X1 SS gm W 3,096,689 7/1963 Kytta ..92/99 x [22] Filed: Sept. 18, 19703,397,621 8/1968 Groves ..92/48 [21] Appl' 29360 Primary Examiner-MartinP. Schwadron Assistant Examiner-Leslie J. Payne Related Application DataAttorney-John R. Faulkner and Robert E. McCollum [62] Division of Ser.No. 858,567, Sept. 11, 1969, Pat. No.

3,599,614. [57] ABSTRACT A vacuum motor having two independently mountedand [52] US. Cl ..92/48, 92/100 movable flexible diaphragms mounted in acommon housing [51] lnt. Cl ..F0lb 19/00 and partitioning the housingimo fl id chambers, one f the Field 01 Search diaphragms having alimited movement and at times limiting 1/ 369 369 7 7 the movement ofthe other diaphragm, the other being connected to a means to beactuated. [56] References Cited UNITED STATES PATENTS Hill ..60/54.6

8 Claims, 8 Drawing Figures PATENTED L I 3.678.806 sum 1 or 5 AT'TORNEYS PKTENTED I973 3.678.806

sum 2 or 3 INVENTOR. Few/m 44. 4777181062 ATTORNEYS 1 DUAL DIAPHRAGMDISTRIBUTOR This application is a division of Ser. No. 858,567, DUALDIAPHRAGM DISTRIBUTOR, filed Sept. ll, 1969, now US. Pat. No. 3,599,614issued on Aug. 17, 1971.

This invention relates, in general, to a fluid motor construction. Morespecifically, it relates to a dual diaphragm vacuum motor assemblycontained within a single housing.

Anti-Smog regulations relating to internal combustion engine exhaustemission controls point out the desirability of a retarded ignitiontiming at engine idle and deceleration conditions as well as a rapidshift to normal timing at all other engine operating conditions. Theretarding of the ignition timing during idle and deceleration produces amarked reduction in engine exhaust hydrocarbon emissions, whereas arapid shift to normal ignition timing allows starting ease and minimumloss of engine performance and economy.

Devices are known in the prior art for automatically advancing orretarding the engine distributor advance plate to control the sparktiming. However, these devices generally require a plurality of separateand remote elements, which increase the overall cost of the engine andcomplexity of the system.

The invention relates to a dual diaphragm vacuum motor assembly within asingle housing that operates automatically in conjunction with othercontrols to properly regulate the movement of the ignition distributorspark advance and retard mechanism to provide the desired retarding oradvancing of the spark at all engine operating conditions.

It is an object of the invention, therefore, to provide a dual diaphragmfluid motor assembly having a pair of coaxially mounted and axiallyspaced annular diaphragms mounted within a single housing forindependent movement at times, and conjoint movement at other times.

It is another object of the invention to provide a vacuum motor assemblyfor an ignition distributor that automatically advances or retards theignition timing as a function of the engine operating conditions asdetermined by the change in flow of the air-fuel mixture through thecarburetor, and by the change in intake manifold vacuum ofthe engine.

It is still a further object of the invention to provide a vacuum motorassembly consisting of two coaxially mounted, independently'movable,flexible diaphragms mounted within a common housing to partition thehousing into separate fluid or vacuum chambers; one being connected to aportion of an engine carburetor above the throttle valve, the otherbeing connected to the carburetor below the throttle valve at a pointleading to the intake manifold; one of the diaphragms being connected tothe distributor advance plate and cooperating at times with the otherdiaphragm to have a limited movement in one direction while beingessentially freely movable in the opposite direction; the otherdiaphragm having a limited movement in both directions to at timescontrol the movement of the sparkadvance plate while at other timesbeing ineffective to provide such control.

Other objects, features and advantages of the invention will become moreapparent upon reference to the succeeding detailed description thereof,and to the drawings illustrating the preferred embodiment thereof,wherein;

FIG. I illustrates, schematically, an internal combustion engine sparktiming control mechanism embodying the invention;

FIG. 2 is a cross-sectional view of the vacuum motor illustrated in FIG.1;

FIGS. 3 and 4 are end elevational views, with parts broken away and insection, taken on planes indicated by and viewed in the direction of thearrows 3-3 and 4-4, respectively, of FIG. 2; and,

FIGS. 5, 6, 7, and 8 are cross-sectional views similar to FIG. 2illustrating the parts therein in various operative positionscorresponding, respectively, to engine starting and wide open throttlepositions, engine idling position, part throttle operation, and enginedeceleration operation.

FIG. 1 shows, schematically, those portions of an internal combustionengine that are interrelated with the vacuum motor assembly of theinvention to provide for an automatic retardation or advancement of theengine distributor ignition timing. More specifically, 10 indicates, ingeneral, an ignition distributor of the centrifugal advance type havingan ignition timing advance plate 12. The plate surrounds theconventional rotor cam 14 and is pivoted for movement about a point 16fixed to the stationary distributor housing, not shown. Rotor cam 14cooperates with a set of breaker points 18 by means of an actuator 20secured to one arm of the breaker points set, as shown. Advance plate 12is pivotally secured at 22 to a reciprocatable actuating rod 24 that isadapted to be moved in a manner to be described by the dual diaphragmvacuum motor assembly 26 embodying the invention.

At the opposite sides of the vacuum motor assembly is shown a portion 28of a carburetor of the conventional downdraft type. It has the usualair-fuel induction passage 30 containing a fixed area ventun' 32 and aconventional throttle valve 34 pivotally mounted on a portion of thecarburetor housing to control flow from manifold 36.

In general, vacuum motor assembly 26 includes two flexible diaphragms,each of which forms a fliuid or vacuum chamber with the housing toprovide various control movements of the advance plate actuating rod 24.The chamber closest to the distributor is connected by a hose or line 38directly to the vacuum of the engine intake manifold through carburetorport 40 that opens into the carburetor below throttle valve 34. It willbe clear, of course, that port 40 could be located to open directly intointake manifold 36. The other vacuum motor chamber is connected by ahose or line 42 through a shuttle valve controlled mechanism 44 and aport 46 to a point in carburetor induction passage 30 above throttlevalve 34, it is in its idle position.

Shuttle valve 44, referred to as a deceleration control valve, or decelvalve, is controlled in its movement by the level of the intake manifoldvacuum, abranch line 47 connecting the intake manifold vacuum in line 38to act on the valve. Below a predetermined intake manifold vacuum, thevalve connects carburetor port 46 to vacuum motor hose 42, vacuum abovethis point moving the shuttle valve to connect intake manifold vacuum inbranch line 47 to hose 42.

Decel valve 44, in this case, comprises a reciprocable valve alternatelyseatable against two ports 48 and 49 as a function of the differentialforce between intake manifold vacuum in line 47 applied to one side of adiaphragm 50 opposed by the force of a tension spring 51. As statedpreviously, the valve determines whether carburetor port pressure inline 46 or intake manifold vacuum in line 47 will be applied to thevacuum motor chamber connected to hose or line 42.

The manifold vacuum level necessary to actuate the shuttle valve, inthis case, would occur only during deceleration operation of the engine,at which time a higher than normal intake manifold vacuum is present inthe system.

FIGS. 2 through 4, which are essentially to scale, show the details ofconstruction of vacuum motor assembly 26. More specifically, the vacuummotor has an outer housing 52, that includes a bell-like, hollow, lefthand portion 53, and a donutshaped, right hand portion 54, the latterhaving a stepped diameter central opening 56. Axially between the twohousing portions is a ring-like spark advance stop plate 58 contiguousto a ring-like spark retard stop plate 60. The latter has a steppedinner diameter 62 defining, with stop plate 58, an annular groove 64.Projecting into and axially movable within groove 64 is the bent edge 66of a washer-like diaphragm retainer 68. The latter retainer, togetherwith a cup-shaped apertured retainer 70, is clamped to an annularflexible diaphragm 72 having a central aperture 74. The diaphragmextends across the hollow interior of the housing and is sealinglymounted at its outer edge between stop plate 60 and the flange onhousing portion 54.

A spring 78 normally biases the diaphragm 72 to the position shownlocating flange edge 66 against the face of advance stop plate 58. Thediaphragm, together with the walls of houspassage 30 to the engineintake ing portion 54, defines a fluid or vacuum chamber 80. Chamber 80is connected to intake manifold vacuum hose 38, as best seen in FIG. 4.

A second flexible annular diaphragm 82 is sealingly mounted betweenhousing portions 53 and stop plate 58, and extends across the housing todefine with it a fluid or vacuum chamber 84. Chamber 84, as best seen inFIG. 3, is connected to hose 42, leading to shuttle valve 44 in FIG. 1.The two housing portions and stop plates and diaphragms are fixedlysecured together by means of an annular cap plate 85.

Distributor advance plate actuating rod 24 is fixedly secured to whatwill be termed primary diaphragm 82 by means of two cup-shaped plates 86and 88 so that movement of the diaphragm in either direction will causea corresponding movement of the distributor advance plate 12 (FIG. 1).The radially outermost bent edge 90 of plate 88 at times is adapted toabut the inner edge of what will be termed the secondary diaphragm stopplate 68 to limit movement of the primary diaphragm in one direction,for a purpose to be described later. A spring 92 normally biases theprimary diaphragm 82 and rod 24 to the right to seat or abut edge 90against plate 68.

The forces of secondary chamber spring 78 is chosen to be greater thanthat of spring 92 so that, all other conditions being equal, thesecondary stop member 66 is positioned against the face of the advanceplate 58, as shown.

The invention will be more fully understood by reference to FIGS. 5through 8 illustrating, progressively, the various modes of operation.FIG. 5 illustrates the operation when the internal combustion engineeither is off and ready to start, or operating at wide open throttleconditions. Taking first the engine off or starting conditions ofoperation, and referring also to FIG. 1; with the engine off, there isno airflow through the carburetor into the intake manifold, and thepressure level at both ports 46 and 40 and in both hoses 42 and 38 isatmospheric. Thus, atmospheric pressure forces acting on diaphragms 72and 82 permit secondary diaphragm spring 78 to seat stop flange 68against the face of advance plate 58, the primary advance spring 92seating primary diaphragm 82 as shown with the flange edge 90 againststop flange 68. Actuating rod 24, therefore, is positioned at this timeto provide the spark timing desired for starting of the engine.

It will also be seen that the position shown in FIG. 5 corresponds towide open throttle operating conditions. That is, at wide open throttle,intake manifold vacuum is essentially at atmospheric pressure. Also,throttle valve 34 is rotated wide open and port 46, therefore, also isessentially at atmospheric pressure; therefore, the same pressureconditions exist in the primary and secondary diaphragm chambers 84 and80 as at engine starting, and actuating rod 24 remains in the sameposition shown and described.

Assume now that the engine has been started, and throttle pedal 34 is inthe closed position shown in FIG. 1, for idle speed operation. Referringto FIG. 6, intake manifold vacuum at this time is high and reflected inthe hose 38 (FIG. 4) to secondary diaphragm chamber 80. The manifoldvacuum is sufficient at this time to overcome the force of spring 78 andpull diaphragm 72 to the right until the stop 66 abuts the face ofretard stop plate 60. Simultaneously, the intake manifold vacuum beingbelow the level sufficient to actuate decel valve 44, and carburetorspark port 46 being essentially at atmospheric pressure, atmosphericpressure is applied through hose or line 42 to primary diaphragm 82 tomove it to the right until it is stopped by abutment against thesecondary diaphragm stop 68. Thus, actuating rod 24 will have been movedto the maximum retard position shown.

FIG. 7 illustrates the positions of the parts during part throttleengine operation. More specifically, when the throttle lever 34 in FIG.I is rotated counterclockwise past port 46 to provide acceleration ofthe engine, the intake manifold vacuum then acts through port 46 andline 42 and chamber 84 to pull primary diaphragm 82 to the left to theposition indicated in FIG. 7. The exact position of the diaphragm, ofcourse, will depend upon the position of the throttle lever. In thisposition, the distributor advance plate actuating rod 24 has been movedto the left to advance the timing progressively, in the normal manner.Simultaneously, the intake manifold vacuum acting in the secondarydiaphragm chamber has decreased sufi'- ciently to permit spring 78 tomove secondary diaphragm 72 to the left of the position indicated, thatis, the advance position moving stop member 66 against the face ofadvance plate 58. Thus, under these circumstances, the primary diaphragmhas moved independently of secondary diaphragm 72 to provide ignitiontiming adjustment in a normal manner. FIG. 8 illustrates the positionsof the parts during an engine decelerating operating condition. At thistime, the intake manifold vacuum increases to a level where decel valve44 is actuated to cause manifold vacuum to be directed to primarydiaphragm chamber 84 instead of carburetor spark port pressure orvacuum. Therefore, at this time, a high intake manifold vacuum will pullprimary diaphragm 82 to the left to the position indicated in FIG. 8,and move the advance plate actuating rod 24 to advance the timing anamount dependent upon the level of the intake manifold vacuum.Simultaneously, high intake manifold vacuum acting in the secondarydiaphragm chamber 80 maintains the secondary diaphragm stop flange 66against the retard face of plate 60, as shown. Again the movement of theprimary diaphragm is made independent of the movement of the secondarydiaphragm.

From the foregoing, it will be seen that the invention provides a vacuummotor assembly or construction that pennits independent mounting of thetwo diaphragms in a common housing for independent movement at timeswith respect to each other while at other times providing a limitedmovement of one relative to the other.

While the invention has been shown and described in its preferredembodiment in the drawings, it will be clear to those skilled in thearts to which it pertains that many modifications and changes may bemade thereto without departing from the scope of the invention.

I claim:

1. A fluid motor assembly comprising, a housing, a pair of flexiblediaphragm members each mounted in said housing for an independentmovement relative to the other and each with said housing defining adifferent vacuum chamber, means connecting each of said chambers to aseparate source of fluid varying from a maximum essentially atmosphericpressure level to a minimum sub-atmospheric pressure or vacuum level forreciprocable movement of each of said members as a function of thechanges in vacuum acting thereon, spring means biasing each of saiddiaphragm members towards the other, movable actuating means connectedto one of said diaphragm members for movement therewith, and means onsaid one member of the said pair of diaphragm members engageable attimes with the other of said members upon movement of said one member inone direction for limiting the movement of said one member in said onedirection in a variable manner as a function of the position of saidother of said members.

2. A fluid motor assembly as in claim 1, including a stop means in thepath of movement of one of said pair of members providing a limitedmovement of said latter one diaphragm member.

3. A fluid motor assembly as in claim 1, said members being coaxiallymounted and axially spaced from each other for independent axialmovement at times of each of said members.

4. A fluid motor assembly as in claim 1, said spring means each having apreload of a different value.

5. A fluid motor assembly as in claim 2, including first means securedto said other of said pair of members for movement therewith, said stopmeans being secured to said housing and projecting into the path ofmovement of said first means on opposite sides thereof.

6. A fluid motor assembly as in claim 3, including first means securedto the said other of said members for axial movement therewith, saidstop means being secured to said housing and projecting into the path ofmovement of the said first means on opposite axial sides thereofproviding a limited axial movement of the said other of said members.

7. A fluid motor assembly as in claim 2, said other member including adisk with a central aperture, said one member including a disk, saidactuating means being connected to a central portion of said latter onedisk and movably projecting through the aperture of said other memberdisk.

8. A fluid motor assembly comprising, a hollow annular housing, firstand second flexible diaphragm members coaxially mounted in and eachextending across said housing for axial reciprocable movement and eachtogether with said housing defining a separate fluid chamber, meansconnecting a separate source of fluid under pressure to each of saidchambers to act on the diaphragm member associated therewith, saidsources each varying in pressure from a maximum essentially atmosphericpressure level to a minimum sub-atmospheric pressure or vacuum level formovement of each of said diaphragm members as a function of the changesin pressure level in said chambers, spring means biasing each of saiddiaphragm members towards the other, said spring means having differentforce values relative to each other, said first diaphragm memberincluding a centrally apertured disk, said second diaphragm memberhaving movable means to be actuated secured thereto and projectingaxially through the aperture of said first disk for axial movementrelative to said first disk, said first disk having radial flange meanssecured thereto, annular stop means secured to said housing andprojecting radially inwardly and straddling said flange means with axialclearance therebetween permitting limited axial movement of said firstmember in opposite directions, and stop flange means secured to saidsecond disk and abuttable at times with the flange means on said firstdisk for limiting at times the movement of said second disk in onedirection of movement, said limiting movement in said one directionvarying as a function of the position of said first disk.

1. A fluid motor assembly comprising, a housing, a pair of flexible diaphragm members each mounted in said housing for an independent movement relative to the other and each with said housing defining a diFferent vacuum chamber, means connecting each of said chambers to a separate source of fluid varying from a maximum essentially atmospheric pressure level to a minimum sub-atmospheric pressure or vacuum level for reciprocable movement of each of said members as a function of the changes in vacuum acting thereon, spring means biasing each of said diaphragm members towards the other, movable actuating means connected to one of said diaphragm members for movement therewith, and means on said one member of the said pair of diaphragm members engageable at times with the other of said members upon movement of said one member in one direction for limiting the movement of said one member in said one direction in a variable manner as a function of the position of said other of said members.
 2. A fluid motor assembly as in claim 1, including a stop means in the path of movement of one of said pair of members providing a limited movement of said latter one diaphragm member.
 3. A fluid motor assembly as in claim 1, said members being coaxially mounted and axially spaced from each other for independent axial movement at times of each of said members.
 4. A fluid motor assembly as in claim 1, said spring means each having a preload of a different value.
 5. A fluid motor assembly as in claim 2, including first means secured to said other of said pair of members for movement therewith, said stop means being secured to said housing and projecting into the path of movement of said first means on opposite sides thereof.
 6. A fluid motor assembly as in claim 3, including first means secured to the said other of said members for axial movement therewith, said stop means being secured to said housing and projecting into the path of movement of the said first means on opposite axial sides thereof providing a limited axial movement of the said other of said members.
 7. A fluid motor assembly as in claim 2, said other member including a disk with a central aperture, said one member including a disk, said actuating means being connected to a central portion of said latter one disk and movably projecting through the aperture of said other member disk.
 8. A fluid motor assembly comprising, a hollow annular housing, first and second flexible diaphragm members coaxially mounted in and each extending across said housing for axial reciprocable movement and each together with said housing defining a separate fluid chamber, means connecting a separate source of fluid under pressure to each of said chambers to act on the diaphragm member associated therewith, said sources each varying in pressure from a maximum essentially atmospheric pressure level to a minimum sub-atmospheric pressure or vacuum level for movement of each of said diaphragm members as a function of the changes in pressure level in said chambers, spring means biasing each of said diaphragm members towards the other, said spring means having different force values relative to each other, said first diaphragm member including a centrally apertured disk, said second diaphragm member having movable means to be actuated secured thereto and projecting axially through the aperture of said first disk for axial movement relative to said first disk, said first disk having radial flange means secured thereto, annular stop means secured to said housing and projecting radially inwardly and straddling said flange means with axial clearance therebetween permitting limited axial movement of said first member in opposite directions, and stop flange means secured to said second disk and abuttable at times with the flange means on said first disk for limiting at times the movement of said second disk in one direction of movement, said limiting movement in said one direction varying as a function of the position of said first disk. 